The capacity for DNA repair is essential to maintain both genetic integrity and normal cellular function and to control abnormal cell growth. Folate is required for biosynthesis of oligonucleotides needed for DNA repair mechanisms and inadequate folate has been associated with human cancer. The methylenetetrahydrofolate reductase (MTHFR) enzyme is critical in the regulation of folate and methionine metabolism. Because folate is important in DNA synthesis, repair and methylation, it may play a role in cancer prevention and recent evidence suggests that this is the case. The overall goal of this study is to determine whether the prevalence of the C677T and A1298C polymorphisms in the MTHTR gene differs between pancreatic cancer patients and control subjects. DNA will be examined from 334 cases and 966 control participants who had blood drawn in the large population-based case-control study that included 550 pancreatic cancer patients and 1600 controls. All genetic testing will be done using the UCSF Comprehensive Cancer Center Genome Core facilities and laboratory personnel. Data analyses for the variables collected in the interviews in the large study and for the MTHFR genetic component also will be completed variables collected in the interviews in the large study and for the MTHFR genetic component also will be completed under the proposed work. The specific aims are to: 1) identify and compare the incidence of MTHFR C677T and A1298C polymorphisms in pancreatic cancer patients and control subjects; 2) evaluate the relationships between MTHFR polymorphisms and other exposures that also may be related to risk for pancreatic cancer such as dietary folate, smoking and alcohol consumption; and 3) perform analyses of other dietary factors and other data collected in the parent study. Data will be analyzed using stratification and multiple logistic regression for all risk factors that could potentially confound or modify the association between the MTHFR polymorphisms and pancreatic cancer such as dietary folate, smoking and alcohol consumption. Data from other risk factors also will be analyzed. While a relationship between low serum folate and risk for pancreatic has been reported there is no data to describe polymorphisms in MTHFR genes among pancreatic cancer patients and control subjects. These questionnaire- and genetics-based analyses will provide new and provocative data of public health importance for this devastating disease.